A container on apron may drift and collide with a coastal structure when a tsunami or a storm surge comes to a harbor. It is important to predict the behavior of container to reduce damages of coastal structures, however, tracking of the motion of container is difficult in a numerical model using a computational grid. Therefore, in this study, the behavior of drifting container due to tsunami is simulated by using the particle method, in which a moving object is easily treated, and the applicability of the particle method is examined.